Vehicle control device

Abstract

To more securely execute restart of an internal combustion engine even when a crankshaft is rotating.SOLUTION: A control device executes automatic stop processing for interrupting combustion of fuel in a cylinder and controlling a throttle valve to a closed state when a predetermined condition is satisfied. In the case where engine speed NE when a restart request of an internal combustion engine is made is zero, the control device executes first calculation processing for calculating fuel injection amount relative to an initial explosion cylinder on the basis of a position of a piston of the initial explosion cylinder. In the case where the engine speed NE when the restart request of the internal combustion engine is made is higher than zero, the control device executes second calculation processing for calculating the fuel injection amount relative to the initial explosion cylinder on the basis of the engine speed NE.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to Vehicle control device Regarding. [Background technology]

[0002] The internal combustion engine of Patent Document 1 includes a cylinder, an intake passage, an exhaust passage, a piston, a crankshaft, a fuel injection valve, and a throttle valve. The cylinder is a space for burning fuel. The intake passage introduces intake air into the cylinder. The exhaust passage discharges exhaust gas from the cylinder. The piston reciprocates within the cylinder. The crankshaft rotates due to the reciprocating motion of the piston. The fuel injection valve supplies fuel into the cylinder. The throttle valve is located midway through the intake passage. The throttle valve adjusts the amount of intake air flowing through the intake passage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-095155 A Summary of the Invention [Problem to be solved by the invention]

[0004] An internal combustion engine control device such as that in Patent Document 1 may execute a restart process to restart the internal combustion engine after stopping the combustion of fuel in the cylinders of the internal combustion engine. Here, an internal combustion engine control device such as that in Patent Document 1 may execute the restart process before the rotation speed of the crankshaft of the internal combustion engine reaches zero after stopping the combustion of fuel in the cylinders of the internal combustion engine. However, the conventional restart process is based on the premise that the crankshaft is stopped. Therefore, in the conventional restart process, when the restart process is executed in a state in which the rotation speed of the crankshaft is not zero, the internal combustion engine cannot necessarily be restarted appropriately. [Means for solving the problem]

[0005] To solve the above problems vehicle The control device of the present invention is an internal combustion engine including a cylinder for burning fuel, an intake passage for introducing intake air into the cylinder, an exhaust passage for discharging exhaust gas from the cylinder, a piston for reciprocating within the cylinder, a crankshaft that rotates due to the reciprocating motion of the piston, a fuel injection valve for supplying fuel into the cylinder, and a throttle valve that is located in the intake passage and adjusts the amount of intake air flowing through the intake passage. a clutch that switches a connection state between an engaged state and a released state, a motor generator including a rotating shaft that is connected to the crankshaft via the clutch, and drive wheels that are connected to the crankshaft via the clutch and the rotating shaft. a control device applied to a cylinder that is an initial explosion cylinder when restarting the internal combustion engine from a state in which fuel combustion in the cylinder has been interrupted, the control device comprising: an automatic stop process that interrupts fuel combustion in the cylinder and controls the throttle valve to a closed state when a predetermined condition is satisfied, when the cylinder that burns first is an initial explosion cylinder, a first calculation process that calculates a fuel injection amount for the initial explosion cylinder based on a position of the piston in the initial explosion cylinder when a rotation speed of the crankshaft is zero when the restart request is made; and a second calculation process that calculates a fuel injection amount for the initial explosion cylinder based on the rotation speed when the rotation speed is higher than zero when the restart request is made. a cranking process in which, when the rotational speed at the time when the restart request is made is equal to or lower than a predetermined specified rotational speed, a connection state of the clutch is controlled to an engaged state and a torque is applied from the rotating shaft to the crankshaft via the clutch to increase the rotational speed; and a release process in which, when the rotational speed at the time when the restart request is made is higher than the specified rotational speed, a release process is controlled to a release state of the clutch. It is possible to execute the following.

[0006] Even when the automatic stop process is being performed, if the crankshaft is rotating, gas flows in the order of the intake passage, the cylinder, and the exhaust passage. When gas flows in this manner, the pressure of the gas downstream of the throttle valve in the intake passage tends to change according to the rotation speed of the crankshaft. As a result, the amount of intake air introduced into the initial explosion cylinder when restarting the internal combustion engine, and therefore the amount of fuel to be supplied to the initial explosion cylinder, also change. According to the above configuration, in the second calculation process, the amount of fuel injection for the initial explosion cylinder can be calculated taking into account the amount of fuel to be supplied to the initial explosion cylinder, which changes according to the rotation speed of the crankshaft. This makes it possible to more reliably restart the internal combustion engine even when the crankshaft is rotating.

[0007] In the above configuration, when "N" is an integer equal to or greater than 2, when restarting the internal combustion engine, it is possible to further execute an intermediate calculation process for calculating the fuel injection amount for the cylinders from the cylinder that burns second most to the cylinder that burns Nth most, and a normal calculation process for calculating the fuel injection amount for the cylinders from the N+1th cylinder onwards, and the value of N used when the rotational speed at the time when the restart is requested is higher than zero may be a smaller value than the value of N used when the rotational speed at the time when the restart is requested is zero.

[0008] According to the above configuration, when the rotation speed of the crankshaft is higher than zero when a request to restart the internal combustion engine is made, the calculation mode of the fuel injection amount is switched to the normal calculation processing earlier than when the rotation speed of the crankshaft is zero. In other words, the restart of the internal combustion engine, in which a relatively large fuel injection amount is calculated, is ended earlier and the control is returned to the normal control of the internal combustion engine. Therefore, the fuel consumption amount when the internal combustion engine is restarted can be reduced.

[0009] In the above configuration, the value of N used when the rotation speed when the restart request is made is higher than zero may be a smaller value as the rotation speed when the restart request is made is higher.

[0010] According to the above configuration, when a request to restart the internal combustion engine is made and the rotation speed of the crankshaft is high, the calculation mode of the fuel injection amount is switched to the normal calculation processing earlier when the restart of the internal combustion engine can be completed earlier.

[0011] In the above configuration, if the rotational speed at the time when the restart request is made is higher than zero, the cylinder into which fuel can be injected first after the restart request is made may be set as the initial explosion cylinder, regardless of the position of the piston at the time when the restart request is made.

[0012] For example, if the rotation speed of the crankshaft is zero when a request to restart the internal combustion engine is made, a process of postponing fuel injection may be executed based on the position of the piston when a request to restart the internal combustion engine is made. According to the above configuration, it is possible to prevent a cylinder in which fuel injection can be executed from becoming a cylinder that does not correspond to the initial explosion cylinder due to the execution of the above-mentioned postponing process or the like. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic configuration diagram of a vehicle. [Diagram 2] 1 is a schematic diagram of an internal combustion engine. [Diagram 3] 4 is a flowchart showing restart control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <Vehicle mechanical configuration> An embodiment of the present invention will now be described with reference to Figures 1 to 3. First, the mechanical configuration of a vehicle 100 will be described.

[0015] As shown in Fig. 1, a vehicle 100 includes an internal combustion engine 10. As shown in Fig. 2, the internal combustion engine 10 includes a plurality of cylinders 11, an intake passage 12, an exhaust passage 13, a plurality of pistons 16, a plurality of connecting rods 17, and a crankshaft 18.

[0016] As shown in FIG. 2, the cylinder 11 is a space for burning a mixture of fuel and intake air. In this embodiment, the internal combustion engine 10 includes six cylinders 11. The internal combustion engine 10 is a so-called in-line six-cylinder engine in which the six cylinders 11 are arranged in a row. In the following, when the six cylinders 11 are collectively described, they are simply referred to as cylinders 11. When the six cylinders 11 are individually described, they are referred to as the first cylinder 11A, the second cylinder 11B, the third cylinder 11C, the fourth cylinder 11D, the fifth cylinder 11E, and the sixth cylinder 11F in the order in which the six cylinders 11 are arranged. In FIG. 2, only one cylinder 11 is shown as a representative.

[0017] The piston 16 is located inside the cylinder 11. The piston 16 is connected to a crankshaft 18 via a connecting rod 17. The piston 16 reciprocates inside the cylinder 11 as a mixture of fuel and intake air is burned in the cylinder 11. The reciprocating motion of the piston 16 causes the crankshaft 18 to rotate.

[0018] The intake passage 12 is connected to the cylinders 11. The intake passage 12 introduces intake air from outside the internal combustion engine 10 to each cylinder 11. The exhaust passage 13 is connected to the cylinders 11. The exhaust passage 13 discharges exhaust gas from each cylinder 11 to outside the internal combustion engine 10.

[0019] The internal combustion engine 10 includes a throttle valve 21 , a plurality of port injection valves 22 , a plurality of in-cylinder injection valves 23 , a plurality of ignition devices 24 , a plurality of intake valves 26 , and a plurality of exhaust valves 27 .

[0020] The throttle valve 21 is located in the intake passage 12. The throttle valve 21 adjusts the amount of intake air flowing through the intake passage 12. The port injection valve 22 is located in the intake passage 12 near the cylinder 11. The port injection valve 22 injects fuel into the intake passage 12 to supply fuel into the cylinder 11 via the intake passage 12. The internal combustion engine 10 includes six port injection valves 22 corresponding to the six cylinders 11. A portion including a tip of the in-cylinder injection valve 23 is located inside the cylinder 11. The in-cylinder injection valve 23 injects fuel into the cylinder 11 to supply fuel into the cylinder 11. The internal combustion engine 10 includes six in-cylinder injection valves 23 corresponding to the six cylinders 11. In this embodiment, the port injection valve 22 and the in-cylinder injection valve 23 are fuel injection valves that supply fuel into the cylinder 11.

[0021] A part of the ignition device 24 including a tip is located inside the cylinder 11. The ignition device 24 ignites a mixture of fuel and intake air by spark discharge. The internal combustion engine 10 has six ignition devices 24 corresponding to the six cylinders 11. The six ignition devices 24 ignite the first cylinder 11A, the fifth cylinder 11E, the third cylinder 11C, the sixth cylinder 11F, the second cylinder 11B, and the fourth cylinder 11D in this order. In other words, the internal combustion engine 10 goes through a combustion stroke in the order of the first cylinder 11A, the fifth cylinder 11E, the third cylinder 11C, the sixth cylinder 11F, the second cylinder 11B, and the fourth cylinder 11D. Each cylinder 11 repeats an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke every time the crankshaft 18 rotates twice.

[0022] The intake valve 26 is located at the downstream end of the intake passage 12. The intake valve 26 opens and closes the downstream end of the intake passage 12 by a driving force from a valve mechanism (not shown). The internal combustion engine 10 is provided with six intake valves 26 corresponding to the six cylinders 11. The exhaust valve 27 is located at the upstream end of the exhaust passage 13. The exhaust valve 27 opens and closes the upstream end of the exhaust passage 13 by a driving force from a valve mechanism (not shown). The internal combustion engine 10 is provided with six exhaust valves 27 corresponding to the six cylinders 11.

[0023] As shown in FIG. 1, the vehicle 100 includes a clutch 31, a motor generator 40, an automatic transmission 61, a differential mechanism 62, and a plurality of drive wheels 63. The motor generator 40 includes a rotating shaft 41. The rotating shaft 41 is connected to a rotor (not shown) of the motor generator 40. Therefore, the rotating shaft 41 is rotatable relative to a stator (not shown) of the motor generator 40. The rotating shaft 41 of the motor generator 40 is connected to the crankshaft 18 of the internal combustion engine 10 via a clutch 31. The clutch 31 switches the connection state of the clutch 31 between an engaged state and a released state in response to hydraulic pressure supplied to the inside of the clutch 31.

[0024] Furthermore, the rotating shaft 41 of the motor generator 40 is connected to drive wheels 63 via an automatic transmission 61 and a differential mechanism 62. An example of the automatic transmission 61 is a stepped automatic transmission. The automatic transmission 61 can change the gear ratio in stages. The differential mechanism 62 allows a difference in rotation speed to occur between the left and right drive wheels 63.

[0025] <Vehicle Electrical Configuration> 1, the vehicle 100 includes a battery 71 and an inverter 72. When the motor generator 40 functions as a power generator, the battery 71 stores the electric power generated by the motor generator 40. When the motor generator 40 functions as an electric motor, the battery 71 supplies electric power to the motor generator 40. The inverter 72 adjusts the amount of electric power exchanged between the motor generator 40 and the battery 71.

[0026] 1, vehicle 100 is equipped with an accelerator operation amount sensor 81, a vehicle speed sensor 82, and a crank angle sensor 83. The accelerator operation amount sensor 81 detects an accelerator operation amount ACC, which is the amount of operation of an accelerator pedal (not shown) operated by a driver. The vehicle speed sensor 82 detects a vehicle speed SP, which is the speed of vehicle 100. The crank angle sensor 83 detects a crank angle SC, which is the angular position of crankshaft 18.

[0027] As shown in Fig. 1, the vehicle 100 is equipped with a control device 90. The control device 90 obtains a signal indicating an accelerator operation amount ACC from an accelerator operation amount sensor 81. The control device 90 obtains a signal indicating a vehicle speed SP from a vehicle speed sensor 82. The control device 90 obtains a signal indicating a crank angle SC from a crank angle sensor 83. The control device 90 calculates an engine rotation speed NE, which is the rotation speed of the crankshaft 18, based on the crank angle SC.

[0028] The control device 90 calculates the vehicle required driving force, which is a required value of driving force necessary for the vehicle 100 to travel, based on the accelerator operation amount ACC and the vehicle speed SP. The control device 90 determines the torque distribution between the internal combustion engine 10 and the motor generator 40 based on the vehicle required driving force. The control device 90 controls the output of the internal combustion engine 10 and the power running and regeneration of the motor generator 40 based on the torque distribution between the internal combustion engine 10 and the motor generator 40.

[0029] The control device 90 performs various types of control such as adjusting the opening of the throttle valve 21, adjusting the amount of fuel injected from the port injection valve 22, adjusting the amount of fuel injected from the in-cylinder injection valve 23, and adjusting the ignition timing of the ignition device 24 by outputting control signals to the internal combustion engine 10. The control device 90 also outputs a control signal to the inverter 72 in order to control the motor generator 40. The control device 90 then controls the motor generator 40 by adjusting the amount of power exchanged between the motor generator 40 and the battery 71 via the inverter 72.

[0030] The control device 90 outputs a control signal to the clutch 31 to control the connection state of the clutch 31. The control device 90 outputs a control signal to the automatic transmission 61 to control the gear ratio of the automatic transmission 61.

[0031] When a stop condition, which is a predetermined condition, is satisfied, the control device 90 executes an automatic stop process that stops the combustion of fuel in the cylinder 11 and controls the throttle valve 21 to a closed state. Here, one example of the stop condition is that the accelerator operation amount ACC becomes zero, thereby reducing the vehicle required driving force.

[0032] When a predetermined postponement condition is satisfied when restarting the internal combustion engine 10, the control device 90 executes a postponement process, which is a process of postponing the injection of fuel into the cylinder 11 that is undergoing a compression stroke at that time. Here, the postponement condition is, for example, that the position of the piston 16 in the cylinder 11 that is undergoing a compression stroke at the time when a request to restart the internal combustion engine 10 is made is within a specified angle range. One example of the specified angle range is the range from an angle advanced by several tens of degrees from the injection start timing of the direct injection valve 23 to the compression top dead center.

[0033] The control device 90 may be configured as a circuit including one or more processors that execute various processes according to a computer program (software). The control device 90 may also be configured as a circuit including one or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that execute at least a part of the various processes, or a combination thereof. The processor includes a CPU and memories such as RAM and ROM. The memory stores program codes or instructions that are configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any medium that can be accessed by a general-purpose or dedicated computer.

[0034] <Restart control> Next, a description will be given of the restart control executed by the control device 90. The control device 90 executes the restart control when there is a request to restart the internal combustion engine 10 while the internal combustion engine 10 is stopped by the automatic stop process. Here, an example of a case where there is a request to restart the internal combustion engine 10 is when the accelerator operation amount ACC becomes greater than zero, thereby increasing the vehicle required driving force.

[0035] 3, when the control device 90 starts restart control, the control device 90 proceeds to processing of step S11. In step S11, the control device 90 determines whether or not the engine speed NE is zero when a request to restart the internal combustion engine 10 is made. In step S11, when the control device 90 determines that the engine speed NE is zero when a request to restart the internal combustion engine 10 is made (S11: YES), the control device 90 proceeds to processing of step S31.

[0036] In step S31, the control device 90 executes a cranking process. Specifically, first, the control device 90 controls the connection state of the clutch 31 to an engaged state by outputting a control signal to the clutch 31. Then, the control device 90 applies torque from the rotating shaft 41 of the motor generator 40 to the crankshaft 18 of the internal combustion engine 10 via the clutch 31 by outputting a control signal to the inverter 72. As a result, the engine rotation speed NE increases. That is, the control device 90 executes cranking of the internal combustion engine 10 by the motor generator 40. After that, the control device 90 advances the process to step S32.

[0037] In step S32, the control device 90 executes a setting process. Specifically, the control device 90 sets "N" to be used in the intermediate calculation process in step S34, which will be described later. In the following, "N" is an integer equal to or greater than "2." However, "N" used in the intermediate calculation process in step S34 is an integer equal to or greater than "3," and is a predetermined constant value.

[0038] In addition, when restarting the internal combustion engine 10 from a state in which the combustion of fuel in the cylinder 11 is interrupted, the control device 90 sets the initial combustion cylinder, which is the cylinder 11 that will burn first. For example, the control device 90 sets, in principle, the cylinder 11 that is in the compression stroke when a request to restart the internal combustion engine 10 is made as the initial combustion cylinder. However, in this embodiment, the control device 90 permits the execution of the above-mentioned postponement process when the engine speed NE is zero when a request to restart the internal combustion engine 10 is made. Therefore, when executing the postponement process, the control device 90 sets, as the initial combustion cylinder, the cylinder 11 that will be in the compression stroke next to the cylinder 11 that is in the compression stroke when a request to restart the internal combustion engine 10 is made. In the following, the cylinder 11 that will be burned next to the initial combustion cylinder will be simply referred to as the "second cylinder 11". In addition, the cylinder 11 that will be burned Nth, with the initial combustion cylinder being the first cylinder, will be simply referred to as the "Nth cylinder 11". After step S32, the control device 90 advances the process to step S33.

[0039] In step S33, the control device 90 executes a first calculation process for calculating the fuel injection amount for the initial explosion cylinder based on the position of the piston 16 in the initial explosion cylinder when a request to restart the internal combustion engine 10 is made. For example, the control device 90 calculates a smaller value as the fuel injection amount for the initial explosion cylinder as the piston 16 in the initial explosion cylinder is closer to the top dead center. Here, the control device 90 grasps the position of the piston 16 in the initial explosion cylinder based on the crank angle SC. The control device 90 controls the port injection valve 22 and the in-cylinder injection valve 23 based on the fuel injection amount for the initial explosion cylinder calculated by the first calculation process. As a result, fuel is supplied to the initial explosion cylinder. Therefore, when the process of step S33 is executed, the engine speed NE increases. After step S33, the control device 90 advances the process to step S34.

[0040] In step S34, the control device 90 executes an intermediate calculation process for calculating the fuel injection amounts for the second through Nth cylinders 11. For example, the higher the engine speed NE at the time of processing step S34, the smaller the value that the control device 90 calculates as the fuel injection amounts for the second through Nth cylinders 11. The control device 90 controls the port injection valve 22 and the in-cylinder injection valve 23 based on the fuel injection amounts for the cylinders 11 calculated by the intermediate calculation process. As a result, fuel is supplied to the cylinders 11. After step S34, the control device 90 advances the process to step S35.

[0041] In step S35, the control device 90 determines whether or not a predetermined end condition is satisfied. Here, an example of the end condition is that fuel injection into the Nth cylinder 11 has been executed. In step S35, if the control device 90 determines that the end condition is not satisfied (S35: NO), the control device 90 executes the process of step S35 again. On the other hand, in step S35, if the control device 90 determines that the end condition is satisfied (S35: YES), the control device 90 advances the process to step S36.

[0042] In step S36, the control device 90 executes a normal calculation process for calculating the fuel injection amount for the N+1th and subsequent cylinders 11. For example, the higher the engine speed NE and the smaller the vehicle required driving force, the smaller the value calculated by the control device 90 as the fuel injection amount for the N+1th and subsequent cylinders 11. The control device 90 also controls the port injection valve 22 and the in-cylinder injection valve 23 based on the fuel injection amount for the cylinder 11 calculated by the normal calculation process. As a result, fuel is supplied to the cylinder 11. The control device 90 ends the current restart control after step S36. Note that even after the restart control ends, the control device 90 calculates the fuel injection amount by the normal calculation process.

[0043] On the other hand, in the above-mentioned step S11, when the control device 90 determines that the engine speed NE when the restart of the internal combustion engine 10 is requested is higher than zero (S11: NO), the control device 90 advances the process to step S21.

[0044] In step S21, the control device 90 judges whether the engine speed NE when a request to restart the internal combustion engine 10 is made is equal to or lower than a predetermined specified speed A. Here, an example of the specified speed A is several hundred rpm. The specified speed A is determined, for example, as follows. First, a lower limit value of the engine speed NE at which cranking of the internal combustion engine 10 by the motor generator 40 is not required when restarting the internal combustion engine 10 is obtained by experiment or the like. Then, a value that is higher than the obtained lower limit value of the engine speed NE by a certain rotation speed is determined as the specified speed A. In step S21, when the control device 90 judges that the engine speed NE when a request to restart the internal combustion engine 10 is made is equal to or lower than the specified speed A (S21: YES), the control device 90 advances the process to step S41.

[0045] In step S41, the control device 90 executes a cranking process. Here, the contents of the cranking process executed in step S41 are the same as those in step S31. Thereafter, the control device 90 advances the process to step S42.

[0046] In step S42, the control device 90 executes a setting process. Specifically, the control device 90 sets "N" to be used in the intermediate calculation process of step S44 described later. Here, "N" to be used in the intermediate calculation process of step S44 is an integer equal to or greater than "2" and is a smaller value than "N" to be used in the intermediate calculation process of step S34. In other words, the value of "N" to be used when the engine speed NE when the restart of the internal combustion engine 10 is requested is higher than zero is a smaller value than the value of "N" to be used when the engine speed NE when the restart of the internal combustion engine 10 is requested is zero. In addition, the control device 90 sets a smaller value as "N" to be used in the intermediate calculation process of step S44, the higher the engine speed NE when the restart of the internal combustion engine 10 is requested. In other words, the value of "N" to be used when the engine speed NE when the restart of the internal combustion engine 10 is requested is higher than zero, the smaller the value.

[0047] Furthermore, when the internal combustion engine 10 is restarted from a state in which the combustion of fuel in the cylinder 11 is interrupted, the control device 90 sets the cylinder 11 that is undergoing a compression stroke when a request to restart the internal combustion engine 10 is made as the initial combustion cylinder. In this embodiment, the control device 90 prohibits the execution of the above-mentioned sending off process when the engine speed NE when a request to restart the internal combustion engine 10 is made is higher than zero. Therefore, the control device 90 sets the cylinder 11 into which fuel can be injected first after a request to restart the internal combustion engine 10 is made as the initial combustion cylinder, regardless of the sending off condition that is the execution condition for the sending off process. In other words, when the engine speed NE when a request to restart the internal combustion engine 10 is made is higher than zero, the control device 90 sets the cylinder 11 into which fuel can be injected first after the request is made as the initial combustion cylinder, regardless of the position of the piston 16 when the request is made. After step S42, the control device 90 advances the process to step S43.

[0048] In step S43, the control device 90 executes a second calculation process to calculate the fuel injection amount for the initial explosion cylinder based on the engine speed NE when a request to restart the internal combustion engine 10 is made. For example, the control device 90 calculates a smaller value as the fuel injection amount for the initial explosion cylinder as the engine speed NE is higher. The control device 90 controls the port injection valve 22 and the in-cylinder injection valve 23 based on the fuel injection amount for the initial explosion cylinder calculated by the second calculation process. As a result, fuel is supplied to the initial explosion cylinder. Therefore, when the process of step S43 is executed, the engine speed NE increases. After step S43, the control device 90 advances the process to step S44.

[0049] In step S44, the control device 90 executes an intermediate calculation process to calculate the fuel injection amounts for the second to Nth cylinders 11. Here, the intermediate calculation process in step S44 is similar to the intermediate calculation process in step S34. After step S44, the control device 90 advances the process to step S45.

[0050] In step S45, the control device 90 determines whether or not a predetermined end condition is satisfied. Here, the process of step S45 is the same as the process of step S35. In step S45, if the control device 90 determines that the end condition is not satisfied (S45: NO), the control device 90 executes the process of step S45 again. On the other hand, in step S45, if the control device 90 determines that the end condition is satisfied (S45: YES), the control device 90 advances the process to step S46.

[0051] In step S46, the control device 90 executes a normal calculation process to calculate the fuel injection amount for the cylinders 11 after the N+1th cylinder. Here, the normal calculation process in step S46 is the same as the normal calculation process in step S36. After step S46, the control device 90 ends the current restart control. Note that even after the restart control ends, the control device 90 calculates the fuel injection amount by the normal calculation process.

[0052] On the other hand, in the above-mentioned step S21, if the control device 90 determines that the engine rotation speed NE when the restart of the internal combustion engine 10 is requested is higher than the specified rotation speed A (S21: NO), the control device 90 proceeds to step S51.

[0053] In step S51, the control device 90 executes a release process. Specifically, the control device 90 controls the connection state of the clutch 31 to a released state by outputting a control signal to the clutch 31. Note that, if the connection state of the clutch 31 is a released state at the time of processing step S51, the control device 90 maintains the connection state of the clutch 31. Therefore, when the processing of step S51 is executed, torque from the motor generator 40 is no longer input to the crankshaft 18. Thereafter, the control device 90 advances the processing to step S52.

[0054] In step S52, the control device 90 executes a setting process. Here, the setting process in step S52 is the same as the setting process in step S42. Thereafter, the control device 90 advances the process to step S53.

[0055] In step S53, the control device 90 executes a second calculation process to calculate the fuel injection amount for the initial explosion cylinder based on the engine speed NE when the restart of the internal combustion engine 10 is requested. Here, the second calculation process in step S53 is the same as the calculation process in step S43. Similarly, the control device 90 controls the port injection valve 22 and the in-cylinder injection valve 23 based on the fuel injection amount for the initial explosion cylinder calculated by the second calculation process. As a result, fuel is supplied to the initial explosion cylinder. Therefore, when the process of step S53 is executed, the engine speed NE increases. After step S53, the control device 90 advances the process to step S54.

[0056] In step S54, the control device 90 executes an intermediate calculation process to calculate the fuel injection amounts for the second to Nth cylinders 11. Here, the intermediate calculation process in step S54 is similar to the intermediate calculation process in step S34. After step S54, the control device 90 advances the process to step S55.

[0057] In step S55, the control device 90 determines whether or not a predetermined end condition is satisfied. Here, the process of step S55 is the same as the process of step S35. In step S55, if the control device 90 determines that the end condition is not satisfied (S55: NO), the control device 90 executes the process of step S55 again. On the other hand, in step S55, if the control device 90 determines that the end condition is satisfied (S55: YES), the control device 90 advances the process to step S56.

[0058] In step S56, the control device 90 executes a normal calculation process to calculate the fuel injection amount for the (N+1)th and subsequent cylinders 11. Here, the normal calculation process in step S56 is the same as the normal calculation process in step S36. Thereafter, the control device 90 advances the process to step S57.

[0059] In step S57, the control device 90 executes an engagement process. Specifically, the control device 90 controls the connection state of the clutch 31 to an engaged state by outputting a control signal to the clutch 31. Thereafter, the control device 90 ends the current restart control. Note that even after the restart control ends, the control device 90 calculates the fuel injection amount by the normal calculation process.

[0060] <Action of this embodiment> For example, in the vehicle 100, the engine speed NE is higher than zero when a request to restart the internal combustion engine 10 is made. In this case, at the time when a request to restart the internal combustion engine 10 is made, the throttle valve 21 is controlled to a closed state by the automatic stop process. However, even if the throttle valve 21 is controlled to a closed state, a small amount of gas can generally flow through the intake passage 12. In the internal combustion engine 10, the engine speed NE is higher than zero. Therefore, in each cylinder 11, gas flows in the order of the intake passage 12, the cylinder 11, and the exhaust passage 13 by repeating the intake stroke, compression stroke, combustion stroke, and exhaust stroke. When gas flows in this manner, the pressure of the gas downstream of the throttle valve 21 in the intake passage 12 tends to decrease as the engine speed NE increases. Then, the amount of intake air introduced from the intake passage 12 to the cylinder 11 decreases as the engine speed NE increases. As a result, the amount of fuel to be supplied to the initial explosion cylinder also decreases.

[0061] Furthermore, the higher the engine speed NE when a request to restart the internal combustion engine 10 is made, the higher the temperature inside the cylinder 11 tends to be. As a result, the amount of fuel that adheres to the inner wall surface of the cylinder 11 due to not vaporizing out of the fuel supplied into the cylinder 11 is likely to decrease. As a result, the amount of fuel that should be supplied to the initial explosion cylinder is reduced.

[0062] <Effects of this embodiment> (1) When the engine speed NE is higher than zero when a request to restart the internal combustion engine 10 is made, the control device 90 executes a second calculation process to calculate the fuel injection amount for the initial explosion cylinder based on the engine speed NE. Therefore, the control device 90 can calculate the fuel injection amount for the initial explosion cylinder by taking into account the amount of fuel to be supplied to the initial explosion cylinder, which changes according to the engine speed NE. This makes it possible to more reliably restart the internal combustion engine 10, even if the engine speed NE is higher than zero when a request to restart the internal combustion engine 10 is made.

[0063] (2) For example, in the vehicle 100, the engine speed NE is zero when a request to restart the internal combustion engine 10 is made, and the send-off condition, which is a condition for executing the send-off process, is not satisfied. In this case, the cylinder 11 that is in the compression stroke when a request to restart the internal combustion engine 10 is made is set as the initial explosion cylinder. At this time, the closer the position of the piston 16 in the cylinder 11 that is in the compression stroke when a request to restart the internal combustion engine 10 is made is to the top dead center, the smaller the amount of intake air present in the cylinder 11 that is in the compression stroke. As a result, the amount of fuel to be supplied to the initial explosion cylinder is also reduced.

[0064] In response to this, when the engine speed NE is zero when a request to restart the internal combustion engine 10 is made, the control device 90 executes a first calculation process for calculating the fuel injection amount for the initial explosion cylinder based on the position of the piston 16 in the initial explosion cylinder. Therefore, it is possible to calculate the fuel injection amount for the initial explosion cylinder by taking into account the amount of fuel to be supplied to the initial explosion cylinder, which changes depending on the position of the piston 16 in the initial explosion cylinder.

[0065] (3) When the engine speed NE when the restart of the internal combustion engine 10 is requested is zero, the control device 90 executes the normal calculation process after the first calculation process and the intermediate calculation process. When the engine speed NE when the restart of the internal combustion engine 10 is requested is higher than zero, the control device 90 executes the normal calculation process after the second calculation process and the intermediate calculation process. Then, the control device 90 calculates the fuel injection amount for the second to Nth cylinders 11 in the intermediate calculation process. Here, the value of "N" used when the engine speed NE when the restart of the internal combustion engine 10 is requested is higher than zero is smaller than the value of "N" used when the engine speed NE when the restart of the internal combustion engine 10 is requested is zero. As a result, when the engine speed NE when the restart of the internal combustion engine 10 is requested is higher than zero, the intermediate calculation process is switched to the normal calculation process earlier than when the engine speed NE when the restart of the internal combustion engine 10 is requested is zero. That is, the restart of the internal combustion engine 10, in which a comparatively large fuel injection amount is calculated, is terminated early, and the control of the internal combustion engine 10 is returned to normal control. As a result, the amount of fuel consumed when the internal combustion engine 10 is restarted can be suppressed.

[0066] (4) In the intermediate calculation process, the value of "N" used when the engine speed NE when the restart of the internal combustion engine 10 is requested is higher than zero is smaller as the engine speed NE when the restart of the internal combustion engine 10 is requested is higher. As a result, the higher the engine speed NE when the restart of the internal combustion engine 10 is requested, the earlier the process switches from the intermediate calculation process to the normal calculation process. In other words, when the restart of the internal combustion engine 10 can be completed earlier, the calculation mode of the fuel consumption switches to the normal calculation process earlier.

[0067] (5) The control device 90 prohibits the execution of the above-mentioned postponement process when the engine speed NE is higher than zero when a request to restart the internal combustion engine 10 is made. Therefore, when the engine speed NE is higher than zero when a request to restart the internal combustion engine 10 is made, the control device 90 sets the cylinder 11 into which fuel injection is first possible after the request as the initial explosion cylinder, regardless of the position of the piston 16 at the time of the request. This makes it possible to prevent, for example, a situation in which the cylinder 11 into which fuel injection is possible is not set as the initial explosion cylinder due to the execution of the postponement process.

[0068] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0069] In the above embodiment, the restart control process may be changed. For example, "N" used in the intermediate calculation process may be changed. As a specific example, in step S42, the control device 90 may set a constant value as "N" used in the intermediate calculation process in step S44, regardless of the engine speed NE when a request to restart the internal combustion engine 10 is made. Even in this configuration, the value of "N" used in the intermediate calculation process in step S44 is preferably smaller than the value of "N" used in the intermediate calculation process in step S34.

[0070] Furthermore, for example, in step S42, the control device 90 may set "N" used in the intermediate calculation process in step S44 to the same value as "N" used in the intermediate calculation process in step S34.

[0071] For example, the end conditions of steps S35, S45, and S55 may be changed. Specifically, the end condition of step S35 may be that the time elapsed since the fuel injection into the initial explosion cylinder has reached a predetermined time period in addition to or instead of the fuel injection into the Nth cylinder 11 being executed. The end conditions of steps S45 and S55 may also be changed in a similar manner. Also, the end conditions of steps S35, S45, and S55 do not need to be the same and may be different from each other.

[0072] In the above embodiment, the control device 90 may omit the postponement process. That is, even if the engine speed NE is zero when a request to restart the internal combustion engine 10 is made, the control device 90 may set the cylinder 11 in which fuel injection is first possible after the request is made as the initial explosion cylinder, regardless of the position of the piston 16 when the request is made.

[0073] In the above embodiment, the configuration of the vehicle 100 may be changed. For example, the vehicle 100 does not need to include the motor generator 40. Even in this configuration, if the engine speed NE is relatively high when a request to restart the internal combustion engine 10 is made, it is possible to restart the internal combustion engine 10 without applying torque from the motor generator 40. Also, if the engine speed NE is zero when a request to restart the internal combustion engine 10 is made, it is possible to restart the internal combustion engine 10 by cranking using a starter motor, for example.

[0074] For example, the internal combustion engine 10 may have five or fewer cylinders 11, or may have seven or more cylinders 11. In addition, for example, the internal combustion engine 10 does not have to be equipped with a port injection valve 22. [Explanation of symbols]

[0075] 10. Internal combustion engine 11…Cylinder 12…Intake passage 13...Exhaust passage 16…Piston 17…Connecting rod 18…Crankshaft 21...Throttle valve 22...Port injection valve 23...In-cylinder injection valve 24...Ignition device 26…Intake valve 27…Exhaust valve 31…Clutch 40…Motor generator 41...Rotation axis 61…Automatic transmission 62…Differential mechanism 63...Drive wheel 71…Battery 72…Inverter 81...Accelerator operation amount sensor 82...Vehicle speed sensor 83...Crank angle sensor 90...Control device 100…Vehicle

Claims

1. an internal combustion engine including: a cylinder for burning fuel, an intake passage for introducing intake air into the cylinder, an exhaust passage for discharging exhaust gas from the cylinder, a piston for reciprocating within the cylinder, a crankshaft that rotates due to the reciprocating motion of the piston, a fuel injection valve for supplying fuel into the cylinder, and a throttle valve located in the intake passage and for adjusting the amount of intake air flowing through the intake passage; a clutch that switches a connection state between an engaged state and a released state; a motor generator including a rotating shaft connected to the crankshaft via the clutch; a drive wheel connected to the crankshaft via the clutch and the rotating shaft; A control device applied to a vehicle equipped with When restarting the internal combustion engine from a state in which fuel combustion in the cylinder has been interrupted, the cylinder in which combustion occurs first is set as an initial explosion cylinder, an automatic stop process for stopping the combustion of fuel in the cylinder and controlling the throttle valve to a closed state when a predetermined condition is satisfied; a first calculation process for calculating a fuel injection amount for the initial explosion cylinder based on a position of the piston in the initial explosion cylinder when a rotational speed of the crankshaft is zero when the restart request is made; a second calculation process for calculating a fuel injection amount for the initial explosion cylinder based on the rotation speed when the rotation speed is higher than zero at the time when the restart request is made; a cranking process for increasing the rotational speed by applying torque from the rotating shaft to the crankshaft via the clutch after controlling a connection state of the clutch to an engaged state when the rotational speed at the time when the restart request is made is equal to or lower than a predetermined specified rotational speed; and a release process for cutting off transmission of torque between the crankshaft and the rotating shaft by controlling a connected state of the clutch to a released state when the rotational speed at the time when the restart request is made is higher than the specified rotational speed. Vehicle control device.

2. When "N" is an integer of 2 or more, an intermediate calculation process for calculating fuel injection amounts for the cylinders from the cylinder that is second to be combusted to the cylinder that is Nth to be combusted when restarting the internal combustion engine; and a normal calculation process for calculating a fuel injection amount for the cylinder (N+1) or later. The value of N used when the rotation speed when the restart request is made is higher than zero is a value smaller than the value of N used when the rotation speed when the restart request is made is zero. The vehicle control device according to claim 1 .

3. The value of N used when the rotation speed when the restart request is made is higher than zero is a smaller value as the rotation speed when the restart request is made is higher. The vehicle control device according to claim 2.

4. If the rotation speed at the time when the restart request is made is higher than zero, the cylinder in which fuel injection is first possible after the restart request is made is determined to be the initial explosion cylinder, regardless of the position of the piston at the time when the restart request is made. The vehicle control device according to any one of claims 1 to 3.

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